Problem with Classics Dinobot raptor head

On my figure in raptor mode, the back of the lower jaw clashes with robot mode's head when I try to open the mouth. Thus, it really won't open at all. But if I force it enough the neck hinge moves as if I'm transforming him. The really weird thing is that it didn't used to do this. It used to work fine. Anybody know what I'm doing wrong, or have any idea wtf is going on?